|MadSci Network: Neuroscience|
N,N-dimethyltryptamine (DMT), is an hallucinogenic tryptamine analog, and an endogenous mammalian hallucinogen. Extensive behavioral and biochemical evidence suggests an agonist role at the 5-HT2A receptor, and perhaps the 5-HT2C receptor, in the mechanism of action of hallucinogenic drugs. DMT behaves as an agonist at both 5-HT2A and 5-HT2C receptors. One difference is in that the 5-HT2C, but not the 5-HT2A, receptor shows a profound desensitization to DMT over time. This difference is interesting in light of the recent report that the hallucinogenic activity of DMT does not tolerate in humans and suggests the 5-HT2C receptor plays a less prominent role in the action of DMT. DMT is not orally active but can be made so by use of MAO Inhibitors. Hallucinogenic effects seen with DMT include a rapidly moving, brightly colored visual display of images. Auditory effects were less common. "Loss of control," associated with a brief, but overwhelming "rush," led to a dissociated state, where euphoria alternated or coexisted with anxiety. These effects completely replaced subjects' previously ongoing mental experience and were more vivid and compelling than dreams or waking awareness. Thus in answer to your question, yes DMT is endogenous and can be made more available through the use of MAOI. Whether this explains near-death experiences I am not sure. It seems that you would expect a more psychedelic experience than the images most people report which are more consistent with an opioid type of response, a feeling of calm and tranquility. References Smith, RL; Canton, H; Barrett, RJ; Sanders-Bush, E. Agonist properties of N,N-dimethyltryptamine at serotonin 5-HT2A and 5-HT2C receptors. Pharmacology, Biochemistry and Behavior, 1998 Nov, 61(3):323-30. Strassman, RJ; Qualls, CR; Berg, LM. Differential tolerance to biological an subjective effects of four closely spaced doses ofN,N-dimethyltryptamine in humans. Biological Psychiatry, 1996 May 1, 39(9):784-95. Hope this helps, gabriel vargas md/phd
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